Andersons pediatric cardiology 1839

Neonatal Stabilization, Surgical Strategies, and Postoperative Management Preoperative Management of the Neonate The general physiologic factors influencing adequate systemic oxygen delivery (DO2) in neonates with a “multidistribution” circulation are discussed in detail in Chapter 70 It is beyond the scope of this chapter to discuss palliative care and nonintervention for infants born with any of the complex anomalies in the spectrum of a fUVH Detailed discussions of the ethics and controversies may be found elsewhere.8,25–30 In addition, this chapter focuses on surgical strategies leading toward a planned Fontan operation Cardiac transplantation is discussed in Chapter 67 The principal goal of preoperative management and stabilization in the neonate with a fUVH is to minimize the risk of future surgical management This general principle contains a number of key components (Box 71.2) Box 71.2 Key Elements of Preoperative Stabilization and Management ■ Monitoring and vascular access ■ Presentation in shock ■ Effects of positive-pressure ventilation ■ Nursing considerations and family support ■ Feeding and nutrition ■ Timing of surgery Monitoring and Vascular Access Despite significant variability in practice, monitoring of the neonate with a fUVH has similar fundamental goals.2 Physiologic monitoring gives the bedside clinician an overview of the dynamic physiologic state of the preoperative multidistribution physiology Stable vascular access allows for infusions of prostaglandin E1 (PGE1), vasoactive medications, and parenteral nutrition In addition, appropriate vascular devices access provide crucial information regarding intravascular pressures, including systolic and diastolic arterial and central venous pressures Co-oximetry data from indwelling vascular catheters can provide valuable estimates of cardiac output and mixing Finally, continuous tracings from vascular lines can provide clues to the physiologic consequences of important residual functional or anatomic abnormalities The risks and benefits of individual monitoring systems and vascular access devices must be carefully considered Although basic devices such as electrocardiography (ECG) and pulse oximetry pose little risk to the patient, invasive devices such as intravascular lines carry the risk of vascular injury, thromboembolic complications, bloodstream infection, and future vascular occlusions Devices must be carefully considered in the context of patient acuity and future vascular needs (Table 71.1) Table 71.1 Common Monitoring for the Preoperative Neonate With a Functionally Univentricular Heart Monitoring Device Electrocardiograph Pulse oximetry Noninvasive blood pressure Invasive arterial catheter Location Right shoulder, left shoulder, left leg Right hand, lower extremity Right upper extremity, lower extremity calf Umbilical artery, femoral artery, radial artery Invasive central venous Umbilical vein, catheter femoral vein, internal jugular vein Near infrared Multisite spectroscopy iDO2 index N/A Electroencephalography Head Indication All Risks Skin irritation All None All Irritation of the extremity, peripheral nerve damage Vascular injury, bleeding, infection Need for continuous assessment of blood pressure and frequent arterial blood sampling Central venous pressure monitoring, hyperosmolar infusions, frequent blood sampling Adjunctive assessment of adequate oxygen delivery Evolving Evaluation of epileptiform activity Vascular injury, bleeding, infection Skin irritation None Skin irritation Electrocardiography Continuous ECG monitoring should be used in all patients with congenital heart disease admitted to the cardiac intensive care unit (CICU) A standard threeelectrode system with leads on the right arm, left arm, and left leg (right and left shoulder and left abdomen in neonates) can provide a single-lead (lead I, II, or III) continuous ECG tracing that accurately detects changes in the heart rate and rhythm along with ischemic changes Continuous monitoring of the ECG tracing can also be utilized in the early detection of electrolyte disturbances, including potassium and calcium Noninvasive Blood Pressure Monitoring An occlusive cuff around the arm and leg of a preoperative neonate is an essential noninvasive monitoring device In neonates, an appropriately sized cuff on the upper arm and calf may be used to monitor arm and calf pressures; these should be essentially identical Noninvasive blood pressure measurements can be made by auscultatory methods or by the use of automated cuffs that use oscillometric methods It should be noted that oscillometric automated cuffs measure systolic and mean arterial blood pressures directly and calculate the diastolic blood pressure Thus interpretation of the diastolic blood pressure calculated by these automated cuffs should be interpreted with this in mind, particularly in with patients where there is diastolic runoff into the pulmonary artery via a patent arterial duct Indwelling Vascular Catheters One of the main advantages of an indwelling vascular catheter is the monitoring of pressure in an arterial or venous vascular structure Pressure monitoring requires the introduction of an end-hole catheter into the vessel to be interrogated Expert technical skill is necessary to place these catheters in preoperative neonates to avoid injury to vascular structures Such catheters are commonly inserted into the umbilical vein, femoral vein, jugular vein, umbilical artery, femoral artery, or radial artery Once placed, the catheter is connected to a pressure transducer via a coupling system that is subsequently connected to the monitor Coupling systems contain tubing filled with a saline solution and a port for zeroing the catheter to atmospheric pressure and withdrawing blood samples Modern transducers contain silicon crystals that change resistance in proportion to the changes in pressure from the coupling system's fluid These systems must be properly calibrated for the accurate assessment of intravascular pressures